Nickel-titanium alloys are commonly used for the manufacture of intraluminal biomedical devices, such as self-expandable stents, stent grafts, embolic protection filters, and stone extraction baskets. Such devices may exploit the superelastic or shape memory behavior of equiatomic or near-equiatomic nickel-titanium alloys, which are commonly referred to as Nitinol.
Nickel-titanium medical devices may be made viewable from outside the body using non invasive imaging techniques, such as x-ray fluoroscopy, by the use of radiopaque markers or coatings on the devices. For example, gold markers attached to one or both ends of a stent may guide the positioning of the device and delineate its length during an x-ray procedure. Alternatively, a medical device may be plated, clad or otherwise coated with gold or another heavy metal to create a radiopaque surface or outer layer. In another approach, a heavy metal cylinder may be included within the lumen of a stent to produce a radiopaque core.